In this work, we introduce a simple, low-cost and acid-resistant materials system for carbon-based screen-printed electrodes (SPEs), and apply it to chemical sensing of hexavalent chromium, i.e. Cr(VI), in acid environments, as encountered in bioremediation of industrial effluents. The developed composite materials comprised of 1) dense organic-carbon conductor, 2) porous polymer-carbon-ligand active sensing material, and 3) insulating and protective dielectric. All materials were formulated with two different organic matrices, polyvinylbutyral (PVB) or epoxy resin (EP). The selected ionophore for chromium detection was diethylenetriamine-pentaacetic acid (DTPA). Both variants allowed Cr(VI) sensing over a wide concentration range in acid media.